Identification_Information:
	Citation:
		Citation_Information:
			Originator: U.S. Geological Survey
			Originator: Coastal and Marine Geology Team(ed.)
			Originator: Western Region
			Publication_Date: Unknown
			Publication_Time: Unknown
			Title: Marine Seismic Reflection Profiles Data of San Francisco Bay Area
			Geospatial_Data_Presentation_Form: remote-sensing image
	Description:
		Abstract:
			Dataset consists of two-dimensional marine seismic
			reflection profile data from the San Francisco Bay area.
			These data were acquired in 1997, with the vessel Davidt
			Johnston.  The USGS identifier for these data is J497SF.
		Purpose:
			Marine seismic reflection data are used to image and
			map sedimentary and structural features of the seafloor
			and subsurface.  These data are useful in mapping
			faults (such as the San Andreas and Hayward Faults)
			where they pass under the waters of the San Francisco
			Bay, and in assessing other submarine geologic
			characteristics and features.
		Supplemental_Information:
			Seismic reflection profiles are acquired by means of an
			acoustic source (usually generated electromagnetically
			or with compressed air), and a hydrophone or hydrophone
			array.  Both elements are typically towed in the water
			behind a survey vessel.  The sound source emits a short
			acoustic pulse, which propogates through the water and
			sediment columns.  The acoustic energy is reflected at
			density boundaries (such as the seafloor or sediment
			layers beneath the seafloor), and detected at the hydro-
			phone.  This process is repeated at intervals ranging
			between  250 milliseconds  and 10 seconds depending
			on the source type.  In this way a two-dimensional image
			of the geologic structure beneath the ship track is
			constructed.
			
			Seismic data are stored in SEG-Y format, which is a
			standard digital format that can  be read and manipulated
			by most seismic-processing software packages.  The
			SEG-Y file format includes a 3200-byte descriptive header
			that should contain detailed information regarding the
			data acquisition and processing parameters.
			
			The navigation data are stored in flat ASCII files as
			latitude and longitude values that can be used to plot
			track maps of the seismic profiles at any scale or map
			projection desired. The data and format of the navigation
			files are described in the file prologue.
	Time_Period_of_Content:
		Time_Period_Information:
			Single_Date/Time:
				Calendar_Date: 19991005
		Currentness_Reference: Publication Date
	Status:
		Progress: Complete
		Maintenance_and_Update_Frequency: None planned
	Spatial_Domain:
		Bounding_Coordinates:
			West_Bounding_Coordinate: -122.29
			East_Bounding_Coordinate: -122.23
			North_Bounding_Coordinate: +37.69
			South_Bounding_Coordinate: +37.61
	Keywords:
		Theme:
			Theme_Keyword_Thesaurus: General
			Theme_Keyword: marine seismic reflection profile
			Theme_Keyword: SEG-Y data
			Theme_Keyword_Thesaurus: Field_id
			Theme_Keyword: J497SF
			Theme_Keyword: David Johnston
		Place:
			Place_Keyword_Thesaurus: Geographic
			Place_Keyword: San Francisco Bay
			Place_Keyword: San Pablo Bay
			Place_Keyword: Golden Gate
			Place_Keyword: Northern California
			Place_Keyword: San Andreas Fault
			Place_Keyword: Hayward Fault
	Access_Constraints: None
	Use_Constraints:
		U.S. Geological Survey requests to be acknowledged
		as the data collector in any publication or other use of
		these data.
	Point_of_Contact:
		Contact_Information:
			Contact_Person_Primary:
				Contact_Person: Jonathan R. Childs
				Contact_Organization: U.S. Geological Survey
			Contact_Position: geophysicist
			Contact_Address:
				Address_Type: mailing and physical address
				Address:
					U.S. Geological Survey
					Mail Stop 999
					345 Middlefield Rd.
				City: Menlo Park
				State_or_Province: CA
				Postal_Code: 94025
			Contact_Voice_Telephone: 650-329-5195
			Contact_Electronic_Mail_Address: jchilds@usgs.gov
Metadata_Reference_Information:
	Metadata_Date: 19991005
	Metadata_Contact:
		Contact_Information:
			Contact_Person_Primary:
				Contact_Person: Clint Steele
			Contact_Address:
				Address_Type: mailing and physical address
				Address:
					U.S. Geological Survey
					Mail Stop 999
					345 Middlefield Rd.
				City: Menlo Park
				State_or_Province: CA
				Postal_Code: 94025
			Contact_Voice_Telephone: 650-329-5055
			Contact_Electronic_Mail_Address: csteele@usgs.gov
	Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
	Metadata_Standard_Version: June 8, 1994